To Save a World
by Xui23
Summary: How far would you go to save the world? Would you sacrifice everything? Yourself? Your family? Is the world truly worth sacrificing for? Reincarnation AU
1. Chapter 1

**To Save A World**

Disclaimer: I own none if this accept any OCs that might appear.

* * *

Sawada Tsunayoshi was famous for all the wrong reasons.

In the tightly knitted neighbourhood of Nanimori, the Sawada family was quite well known.

The beautiful mother, Sawada Nana, showered her twin sons with affection. Loving them both equally. Her husband, Iemitsu, was constantly absent, but was always hard at work to provide for his family. He never failed to call and visit once in a while to check up on his them.

The son, Ienari, was a shy but caring child, whom clearly loved his family. Taught the values of one by his mother, he was seen constantly helping his mother around the house and was never seen without his twin. The whole of Nanimori was infatuated by this perfect angel of a child.

They were the perfect family. A loving mother, a caring son and a hardworking father.

Then, there was the black sheep of the family.

The neighbours gossiped, about him. How he tripped over his own feet. How he still needed to be carried when his twin brother was already out running errands with his mother. How he already 5, yet no one had heard or seen him speak a single word. How he was never quite right in the head.

Yes, Sawada Tsunayoshi was a seemingly useless child who people were sure would never amount to anything. Yet he was blessed with a family who loved him despite everything. Everyone was sure that the no-good boy was nothing but a burden to the family.

However the family strongly disagreed with their opinions.

The first time one neighbourhood gossiper dropped the nickname 'Dame-Tsuna' in front of the Sawada matriarch, Nana had smiled sweetly and invited them over for dinner. Delighted at the chance to try her legendary cooking, the gossiper had immediately agreed.

The next day, they had to be hospitalised for sever food poisoning. When doctors tried to question them on the possible cause of it, they had looked absolutely traumatised. Refusing to speak a single word.

That incident had sparked a rise in food poisoning incidents in the neighbourhood. Many have tried to investigate a cause however nothing conclusive had ever came of it.

Ienari was also known to be very protective of his younger twin. Once, while the family was at a park, Nana was busy chatting with a friend while the twins played in the sand-pit. Tsuna had been building a sand mound when a older boy had come by and kicked it over. Stating, 'The Dame should stop trying to do something productive and just give up in life.' While failing to notice the darkening aura around his twin.

The bully had been subsequently disposed of, receiving a mouthful of sand for every word he had dared speak against Nari's beloved brother.

Nari had then been declared king of the playground.

Nana, after hearing what had happened, had clapped her hands happily, saying 'we have to celebrate Ie-kun's accomplishment', promising to cook her son's favourites for dinner. She of course, had made sure to invite the bully and his mother over.

* * *

"Tsu-kun! Lets go play!" Ienari grinned at his twin.

When he saw Tsuna smile softly and nod, Nari had to hold in the urge to squeal. His twin was so cute! Sure he himself was 5 and by all definitions cute too, but he had long decided that no one could compare to the adorableness that was his brother.

'Also,' Nari thought, 'Mama always says I'll be handsome and cool when I'm big, but tries to make Tsu-kun wear girl clothes.'

It was true. Nari was much bigger than other 5-year-olds. He had bright, spikey blonde hair and sky blue eyes, courtesy of his foreign blood. He was tall and lean, had sharp eyes and strong features. Loose a little baby fat and he would be an absolute heart throb in the future.

While Tsuna, was so small, most would guess he was a younger brother instead of twin. He had large, honey golden eyes, fluffy brown hair and a heart shaped face. One could easily mistake him for a girl.

As Nari found himself caught in fantasies of his cute little twin brother, Tsuna eyed him curiously.

Tsuna knew he wasn't as smart as his Nari-nii but he honestly couldn't understand his twin sometimes. Whenever he smiled at him, Nari-nii would start to stare of into space. He was getting really worried about him. Once Nari-nii had walked right into a street lamp but hadn't even registered the pain until Tsuna pointed out his bloody nose!

Sighing in exasperation, Tsuna clapped his hands in front of his older twin. Effectively snapping him out of his stupor.

"Ie-kun hurry up! Mama won't let us out if the sun's gone!" Tsuna whined.

"Hai, Hai lets go now." Nari made sure to avoid looking at his brother, less he end up cooing at the adorable pout.

Reaching out to take his hand, Nari led his brother out into the yard to play. Making sure to tell his mother where they were going. All while ignoring the unpleasant buzz at the back of his head.

* * *

Tsuna was in a great mood. He had been playing catch with his brother all afternoon, and it was so much fun! Sure he had tripped a few times, but Nari-nii had always made sure to pause the game and patiently put a bandage on his scrapes.

Tsuna was having so much fun he decided to ignore the little voice in his head, telling him to take his brother and go back inside right _now_.

Sure the voice had always been right, like that time it told him to go other way in school allowing him to avoid a bully. Or that time it told him not to drink milk in the fridge which had ended up making Nari-nii sick.

But it could be wrong right? After all no one could be always right. Besides Tsuna was sure that nothing bad could happen on such a great day.

Tsuna turned the corner around the house, running towards the front gate. Nari was hot on his heels, stopping to look over his shoulder, Tsuna smiled victoriously when he saw his brother was still a good distance away. He turned to resume running.

And promptly ran right into a wall of human muscle.

He stepped back, nursing his sore nose as he looked up to see what he bumped into.

He jumped in fright as he took in the sight of a man in a black suit.

The man smiled sinisterly at him and Tsuna took another step back in horror.

Nari was laughing gleefully as he turned the corner.

He stopped dead at the sight of an unknown man reaching towards his frozen brother.

Nari ran forward, "DON'T TOUCH HIM!" He screamed.

The man turned to smirk at him mockingly, before grabbing his frightened twin and lifting him of the ground by his collar.

Tsuna, finally regaining his senses, lets out an ear piercing screech, "HIIIIEEEEE!".

Nari saw red as he lunged at the man. Fury fuelling his actions as clawed at arm holding his brother.

"F***ing brat!" the man cursed and swung his free hand in a backhand. Striking Nari right in the face.

"Ie-kun!" yelled Tsuna in alarm.

Nari fell to the ground in shock. He whimpered in pain, tasting blood as his hand rose to cradle his face.

"Ie-kun? Tsu-kun?" came the worried voice of his mother.

Nari and Tsuna both stiffened simultaneously. Fearing the man would try and hurt their mother.

The man smirked sadistically. He threw Tsuna to the ground and reach into his pocket.

Tsuna yelped as he made contact but quickly scrambled over to his brother to check his injuries.

Suddenly the man wiped out a gun and pointed it at them.

"Go on, be good little boys and go back into the house to reassure your mama." The man beckoned towards the house with his gun.

Beyond scared at this point Tsuna grabbed Nari's arm and made a break for the house.

He was about to slam the door shut when a foot inserted itself in between the door and its frame.

The haunting image of the man peeking in through the crack in the door, smile resembling that of a devil's, had Tsuna stumbling backwards towards his twin.

The door creaked open slowly, tauntingly, as the twins watched in horror.

"Wha-" their mother's voice was abruptly cut of as she walked into their doorway.

Nana screamed in terror at the sight before her. Her babies were in danger!

She shut her mouth abruptly as the man fired a warning shot at her feet.

Nana flinched away but stared defiantly at the man, "What do you want with my children?!"

She twitched as she noticed the injury on her oldest but withheld the urge to run up to him, continuing to study the man.

The man let loose another smirk and Tsuna decided that the thing before him was no man, but a monster from the deepest depths of hell.

"Their deaths."

Tsuna saw the gun pointed at him

It fired.

Something warm splattered on his face.

Tsuna watched as his Mama fell backwards.

And he screamed.

* * *

Nari didn't understand.

The man wanted then dead.

Why? Why? _Why?_

He pointed a gun at Tsuna and Nari knew he had to move.

Because Tsuna was in danger and Tsuna was his little brother.

And Nari had to protect his little brother.

But he _couldn't_ move.

Angry, frustrated tears sprung into his eyes.

 _Why couldn't he move?_

Then there was sound of the gun going off and Nari knew he was going to loose his brother because _he was useless._

But then suddenly Mama was there.

And then Mama was falling.

And Tsuna was screaming.

And so was he.


	2. Chapter 2

" **Mama? Where's Papa?"**

 **Nana paused in her cleaning. Drying her hands from where she had been washing the dishes, she turned to look at her children.**

 **She was confused at the seemingly random question, but answered none the less. "Well, your Papa is out work-"**

" **No! That's not what we want to know!"**

 **Nana stopped and stared at her youngest in surprise, it was rare for him to speak at all, much less interrupt anyone.**

 **Tsuna looked on the verge of tears when Nari cut in.**

" **We heard you cry last night, Mama."**

 **Nana jumped in shock but was immediately flooded with guilt at the worried glances from her children.**

 **No, no, no, what kind of mother was she to worry her children? It was the job of a mother to worry** _ **about**_ **her children.**

 **Tsuna sniffled, "If Papa is making Mama cry then..."**

" **We don't want a Papa!" Nari finished.**

 **Nana's head shot up at their exclamation.**

" **No! Your Papa is working hard to support us! You shouldn't say that about your Papa!"**

 **The twins flinched at her raised voice and their heads lowered in shame.**

 **Nana's eyes soften.**

" **Your Papa loves us very much so he's trying his best to make sure we can live happily."**

" **But he made you cry..."**

" **That's not his fault. It's cause your Mama selfishly misses him," Nana bent down to gather the twins in her arms. "but it's ok though, Mama has the two of you!"**

 **Their eyes widened but they quickly snuggled into her embrace.**

" **I love you two."**

" **We love you too Mama!"**

* * *

"Mama,mama,mama,mama..." Tsuna chanted hysterically as he cradled his Mama's head in his lap.

There was so much red.

Nari crawled over to them, his movements were filled with desperation.

"...Mama?" he chocked.

"...Ie...Tsu" Mama's voice was so soft and gentle.

Sobs wrecked their tiny frames as they watched their Mama struggle to breath.

"Ie plea...se protect Tsu...okay?"

Nari wiped his tears furiously as he nodded, eyes filled with conviction.

"...Tsu you n-need to take c...are of Ie. Your brother loves to p-push him...self so... just be there f-for h...im."

Tsuna sobbed harder. "Pro-promise. I-I promise."

Nana smiled lovingly at her children.

"I lo..."

And she was gone.

"WE LOVE YOU TOO!"

* * *

The twins had barely anytime to grief before they were dragged back into the cruel, _cruel_ reality of their situation.

"Awwwwww. How touching." The ma- monster sneered.

They glared hatefully at him.

"Too bad you still have to die."

The gun was aimed at Tsuna again.

And it fired.

* * *

Nari saw the gun aimed at Tsuna again.

The monster took his Mama. Now it wanted his brother?

NO.

Nari thought of Mama, laying lifelessly in a pool of red.

And he thought of Tsuna, his dear beloved little brother, joining her.

NO! He would protect him.

And then there was _fire_.

* * *

Tsuna saw the bullet coming towards him, almost in slow motion.

In his peripheral, he noticed Nari staring at him in horror and despair.

Tsuna didn't want to leave his brother alone, especially not after he just promised Mama.

'I _won't_ leave Nari alone.'

Suddenly, he felt warmth surround him.

And Tsuna _moved_.

And then, _he remembered._

* * *

He was _so_ close.

The monster screeched in agony as he was sat on fire.

He had worked so hard to get to this point.

He had painstakingly plotted for months to get around the Young Lion's security.

He had already gotten rid of the bastard's wife. Sure he had planned to kill her children in front of her to enjoy the terror and despair on her face.

But unexpectedly she had jumped in front of the bullet made for the brat.

A minor setback.

He had taken aim at brown brat again. But somehow the piece of sh** had dodged the bullet.

And everything had gone to hell.

Suddenly _he_ was on fire. His clothes incinerated and his skin following.

He swirled around to see the blonde brat, with his arm stretched out towards him. Surrounded by orange flames, setting fire to everything and anything around him.

Orange orbs pierced through him as the brat glared.

It was the last thing he saw.

He had been _so_ close.

* * *

Tsuna grabbed his head in white hot pain as his mind was invaded by foreign memories.

He could feel himself loosing consciousness.

The fire was spreading rapidly around him and he knew had to get Nari out.

"NARI!" he yelled.

Nari snapped out of whatever trance he was in as he turned to look at the burning corpse of a man before him.

"Huh?"

"You need to get out!" Tsuna shouted over the loud roar of the raging flames.

"What? Not without you!" he recoiled the very notion.

Tsuna eyes the huge flame separating him from his twin. It was too large.

He shook his head helplessly.

"Please", he begged. "please you need to get out right _now!_ "

"No-no-no, please not you too Tsu-kun!" Nari cried as he fell to his knees.

It was too much. First Mama, then his brother. It was too much.

He just wanted to go to sleep and forget this horrible nightmare.

Tsuna's eyes hardened. "Get up."

Nari unconsciously obeyed. He had never heard anyone speak with so much authority before. Especially not his shy and meek brother.

Tsuna stared pleadingly at his brother.

"Please, Nii-chan go. Live. For us okay?"

Nari stared into his brother's tear stained eyes.

He could never say no to those eyes.

The world around them stopped as Nari stared at his twin, engraving every detail of his face into his memories.

Finally, he turned and bolted out of the open door. Tears streaming behind him as he left his whole world behind.

* * *

Tsuna smiled sadly as he saw his brother leave.

He felt another wave of pain hit him and he knew he was fading out of consciousness.

He turned to look at the body of his Mama wistfully.

'Mama...I'm sorry.'

All of a sudden, he heard a loud cracking noise.

He looked up to see the ceiling give in.

Instinctively, he reached out his arms and flames formed a protective barrier around him, shielding him from danger.

Basking in the warmth, Tsuna finally let himself fall.

* * *

Tsuna woke up to the feeling of being picked up.

"The decoy has failed." Came the gruff voice of a man.

"How?" this one was laced with static. A walkie-talkie?

"A mistake. Our contract apparently had a grudge on the Young Lion. He tried to kill the targets for revenge."

"And the targets?"

"One got away."

"The other?"

"Bringing it back to the lab right now."

"Very well. We just have to settle for one then."

Tsuna didn't really understand but they said someone got away. Was it Nari?

'If Nari is safe then everything is fine.' he thought.

And he once again immerged himself into a sea of foreign memories.


	3. Chapter 3

**Tsuna remembered being 13 and Dame when Reborn came into his life, bringing a whirlwind of chaos and destruction with him.**

* * *

 **A 14-year-old Tsuna looked at his tutor, completely stupefied.**

" **Say what?!"**

 **Reborn tugged at his new fedora, one to fit his now adult body, shadowing his eyes.**

" **Don't make me repeat myself Dame-Tsuna, it has been decided that you and your guardians are to move to Italy to start the final stages of your Decimo training."**

" **But why?!" Tsuna was bother line hysterical, "didn't we agree that I had till at least after high school."**

 **Reborn looked at his student sadly. Tsuna had grown so much from the seemingly useless boy he had first met. He was now a young man with a bright future ahead of him and it was all going to be destroyed because of the mafia.**

" **I'm sorry Tsuna." Tsuna jumped in shock. Reborn never,** _ **ever**_ **apologised. Just as Tsuna was contemplating the consequences of checking for a possible alien invasion, the ex-Arcobaleno continued.**

" **I had hoped you could at least enjoy your childhood, however Nono has been diagnosed with a terminal heart disease. Vongola is running out of time."**

 **Tsuna gulped and he looked down. He had barely just accepted that he was to become a boss after the Representative battles mere weeks ago but he never expected it to happen so soon. He thought he still had time.**

" **B-But what if I'm not ready?" Tsuna squeaked and immediately cringed at the stutter.**

 **Tsuna flinched as he saw Reborn raise his hand. He braced himself for a whack on the head but froze at the feeling of a warm hand ruffling his brown locks.**

" **Listen well, my student, cause I'll only say it once." Tsuna was wondering what alternate reality he had woken up in, because Reborn was smiling at him, not smirking sadistically, not cackling evil but actually smiling!**

" **I'm proud of you."**

 **Tsuna stiffened, and his face was turned a brilliant shade of red.**

" **That's it, Mukuro must've finally managed to trap me in an illusion my Hyper Intuition can't detect." He finally decided.**

 **The hand in his hair paused, before tugging at it painfully.**

" **Well Dame-Tsuna, since you can't even tell the difference between illusion and reality, it seems some re-education is in order."**

" **HIEEEEEE! I'M SORRY!"**

' _ **Thank you, Reborn.'**_

* * *

 **Tsuna was barely 15 when he was forced to take the mantel of the bloodiest mafia famiglia in the world. He was the youngest and strongest boss in Vongola's history.**

* * *

 **Tsuna looked at the stacks of paperwork on his desk in utter despair. They kept multiplying like bunnies!**

 **Tsuna sighed as he picked up a pen to start work. If he had known reforming Vongola would be so much work, he would have given the throne to Xanxus and ran to hide in Antarctica.**

 **Consequences be damned.**

' **It also doesn't help to have destructive guardians racking up the repair bills.' Tsuna looked mournfully at the long line of zeros on the document before him.**

 **Resigned, Tsuna signed the document before moving onto the next. Reading it carefully, he couldn't help the smile appearing on his face.**

 **It was a document listing their earnings from the new hotel chain they had built.**

 **They were making progress. Vongola was no longer only relying on illegal income methods. Tsuna was making a difference.**

 **Smiling brightly, Tsuna tackled his paperwork with renewed vigour.**

* * *

 **Days before his 16 birthday, Vongola officially transitioned from the bloodiest mafia famiglia to the largest vigilante organization in the world with reputable incomes.**

 **Tsuna honestly wondered if he should remember the celebration party fondly or cringe every time it was mentioned.**

* * *

 **Tsuna clenched his trembling hands, trying desperately to calm himself.**

" **Are you really going to go through with this?" his advisor asked.**

 **Tsuna turned a strained smile at him.**

" **Isn't it a little to late for regrets now, Reborn?"**

 **The Italian flicked the brim of his fedora up. He smirked.**

" **Then you'd better stop trembling and do it with you dying will, Dame-Tsuna."**

" **Yah! Jyudaime will be fine! You have us to support you!" His right hand reassured him.**

" **Mah, mah you just need to calm down Tsuna!" Yamamoto placed a hand on his shoulder, calming him with his rain flames.**

 **Tsuna turned to look at the people gathered there to support him. His guardians, the ex-Arcobaleno, Milefiore, the Simon famiglia, the Cavalone, even the Varia and many others who supported his cause. Exchanging a determined nod with them, Tsuna steeled himself.**

 **Vongola Decimo took to the stage gracefully and confidently, surrounded by his closest allies. His cloak flared out around him as he reached out to take the mike.**

 **Glowing amber bled into honey orbs as the Decimo spoke, voice grave and filled with authority.**

" **We of the Vongola Alliance hereby declare," he paused dramatically. "We are waging war on every single mafia famiglia in the world."**

 **The following chaos, by Reborn's description, was glorious.**

* * *

 **Tsuna couldn't even bring himself to celebrate his 17** **th** **birthday.**

* * *

' **17 is to young an age to be a war veteran.' Tsuna thought melancholically.**

 **He could only bring himself to be grateful that he had managed to keep the kids out of everything.**

 **The war had left its marks.**

 **Tsuna would never look at his hands the same way again. They used to be a fumbling mess, he remembered barely being able to hold a pen without dropping it every 5 minutes in class. Now he could eliminate an enemy with them in mere seconds.**

 **The once squishy and pudgy flesh was now marred with scars and callouses, stained with the blood of countless others.**

 **There were times when Tsuna doubted himself. He knew war could never be the right answer and even after so long he still hated to fight, hated that he knew how it felt to have the blood of others flow down his arms.**

 **However he had been left with little choice. Due to his constant meddling in other famiglia's activities, the tensions were rising. He knew that if left be, war would be inevitable.**

 **So he planned. He made use of the uproar caused by the declaration to evacuate the innocents. He led his allies in attacks on other famiglias. Decimating the drug trade and human trafficking. He used Vongola's seemingly infinite resourced to free prostitutes and build homes for orphans and the homeless.**

 **But despite the good they did, Tsuna knew he was no saint.**

 **Because he killed.**

 **He had tried to take prisoners and turn them into the police. But in war, killing was inevitable.**

 **Sometimes, Tsuna questioned his morals. Because there was no way killing could ever be acceptable. Even iv he knee that the people he killed were horrible corrupted people who tried to hurt his family. But did they really deserve the ultimatum that was death?**

 **However, then Reborn would come by and whack him for 'reverting to a Dame' and his guardian would annoy him with all sorts of antics and he could do nothing more but smile and thank them silently.**

 **More than anything, he regretted dragging his guardians into the mafia. Yet they were always quick to reassure him and they never once wavered from their position next to him.**

 **And for that he was eternally grateful.**

* * *

 **Half a year had passed from the war and that was when Tsuna learnt they were going to die.**

" **Tsuna-san, we are all going to die in the near future." Yuni looked at him grimly.**

 **The teacup in his hand pause in its journey to his mouth.**

" **Huh?" was his intelligent response.**

 **In his defence what could one say to that? He had just been enjoying his monthly get together with his fellow Tri-Ni-Sette skies that Byakuran insisted on having when Yuni had dropped a bomb.**

 **Actually screw a bomb, that was a certified nuke.**

 **Byakuran opened his eyes to look at him seriously.**

" **Yuni recently had a vision of our approaching deaths at a great enemy."**

" **Is there no way to avoid it?"**

 **Yuni shook her head sadly. "I'm afraid not, what is to come has already been set in stone. It is unavoidable."**

 **Tsuna slumped in his seat. "Then what are we to do? Sit and wait?" he demanded.**

 **Byakuran smirked and Tsuna immediately sighed in relief. There was hope.**

" **Who said death can stop us?"**

 **Yuni's eyes danced with mirth.**

" **We have much to plan for."**

* * *

 **Tsuna remembered being 17 and dying with a mission.**

' **Stop Sawada Ienari.'**

* * *

Tsuna woke up and he was 5 again.

.

.

.

'Nari-nii?'


	4. Chapter 4

Tsuna studied the cell he was in, trying to keep his thoughts off the inner turmoil of his mind.

It was small, barely a couple metres in length. There were suspicious stains on the wall and there was a pool of dried blood in the corner. The cell reeked of human suffering. Tsuna himself had had his clothed replaced by some shorts and a large grey t-shirt that stopped just above his knees. They were obviously used and both were covered in old blood stains.

Right outside his cell door was a large emblem of a medical cross made out of a scalpel and an injection needle with a snake coiling around it, painted on the wall. He noted that it seemed vaguely familiar and decided to pounder on it some other time.

Tsuna finally paused to collect his thoughts. He had been reincarnated into an alternate version of himself with a mission of preventing a megalomaniac from trying to take over the parallel worlds.

No problem, he could live with that, it came with having to deal with the personification of chaos that was Reborn.

But have said megalomaniac be his sweet loving elder brother?

Nope.

As far as he could remember, Nari had been nothing but a caring sibling. He looked out for Tsuna and went out of his way to help Nana. He was also one of the kindest people Tsuna had ever met in both his lives. He enjoyed helping people and never hesitated to put others before himself. There was no was no way he could be the person that murdered everyone Tsuna ever loved right in front of him in cold blood.

There was no way. He refused to accept it. Tsuna clenched his fists tightly. His kind, beloved brother could never be that power hungry psychopath that sought nothing but death and destruction. There was just no way.

He would find out what in the world had twisted such a good person into ravenous beast, nothing but a shadow of the human being he once was, and he would stop it from ever happening.

He would do it with his dying will. He owned at least that much to his Mama-

Oh god Mama.

Tears started to form in his eyes and Tsuna felt something cold and black curl around his heart as he recalled Nana's final moments.

He had failed her. Just as he had failed his guardians.

And there was no second chance for her. No promises of meeting in another life. No hope of ever seeing her again.

No more of her delicious, warm cooking. Her uplifting smiles. Her soothing hugs.

Mama was gone.

He had lost the chance of ever meeting his other Mama again when he died. And he had lost his Mama of this world, forever.

And it was his fault.

Tsuna stared down at his wrong, wrong, _wrong_ hands. They were still soft and unmarked by hardship.

But then they morphed into hands stained with blood and gore. Hands that held Mama as she slipped away and-

 **Warm blood flowed through his finger. He cradled Mama in his lap. She was looking at him with glassy eyes. Trying and failing to breath. And** _ **No, no, no, no, no you can't die, you can't! I won't loose you. No, no, no, n-**_

Tsuna was snapped out of it as he heard a loud creak. He turned to see the rusty cell door swing open.

A large man dressed in a white lab coat entered his cell and studied him. He took in Tsuna's teary eyes and laboured breathing and smirked.

"Awww. Is the little baby afraid?" he mocked.

Tsuna flinched as he tried, and failed, to calm himself.

The man grinned as he strutted over to the brunet. Tsuna attempted the move back but his legs refused to work.

The man reached out and grabbed Tsuna roughly by the arm. He started to drag him out of the cell.

"I'm sure your confused right now and since I'm so kind, I'll explain it to you." The man pause to leer at him. "You see, you possess some very special qualities in your blood which makes you very valuable to us and our research. So we brought you here to aid in our cause!" He finished brightly.

Tsuna finally managed to clear his mind. Falling back on his training with Reborn, he entered what others had dubbed his 'boss mode'. Forcefully detached himself from his emotions, he considered the situation at hand.

He didn't have time to grieve.

The enemy obviously wanted him for his Vongola blood so that means that Nari would be a target as well.

"Where is my brother?" he demanded.

The man looked at him in surprise, obviously not expecting the previously cowering boy to be so blunt but he quickly recovered and sneered.

"The damn thing got away."

Ignoring the insult, Tsuna sighed in relief. Good, his brother was safe.

Running through his options, Tsuna knew he had to escape and fast. He needed to make it to his mother's funeral. He had to say goodbye one last time. Apologise to her. He needed to reassure his worried sick brother on his survival.

Dying-will flames were of the table as he knew his young body wouldn't be able to take it. He could already feel his entire body aching from the brief usage in the house fire.

So he would have to rely on his martial art skills. That's fine, he learnt from the best after all.

Mind set, Tsuna turned to his captor and his eyes narrowed in determination.

He reached out to grab the hand on his arm and waited as the man turned to face him...

Before promptly kneeing him where to sun didn't shine.

He watched in slight satisfaction as the man 'eep'ed and toppled like a house of cards.

Pausing to bask in sadistic pleasure, he smirked as he took of running but grimaced at the realisation that Reborn was rubbing off on him.

Dashing through the long hallways, he reached into himself to probe at his intuition. He knew it was already active but he also knew it wasn't as developed as it had been in his past life.

A satisfied noise left him as he felt something nudge him toward his right.

Relying on his intuition to guide him, Tsuna soon came to a grey door.

He frowned in confusion. The door seemed no different from the countless others that he passed and his intuition clearly stated it wasn't an exit. So why had it led him here?

Having learnt long ago not to question anything in his life, Tsuna listened to its instructions and pressed his ear against the door. Closing his eyes, he focused on his hearing.

"-done?" asked a male.

"Yes, we have finally entered the final stages of the Blood Eye experiment." This one was distinctly female.

"How long is this damn thing gonna take?" demanded the male.

A sigh. "This is the critical point. The subject needs 6 months to undergo all the stages. Any disturbances to the subject or the computer simulator could end in death, so be patient."

Grumbling. "Damn kid, wasting our precious resources," Tsuna could practically hear the smirk in his voice. "Hope he enjoys his trip to the 6 levels of hell."

At this point, Tsuna had come to a sinking realisation. No longer bothering with stealth, he rammed open the door.

"The hell-?!" came a voice but Tsuna ignored him.

Turing to look at the metal bed in the middle of the room, Tsuna felt his heart drop at the sight of a familiar pineapple head laying in the middle of it, connected to countless other machines.

The scientists in the room were rushing to capture him and some where calling for back up but Tsuna didn't care.

That's why that emblem outside his cell was familiar. Tsuna had been captured by the Estraneo famiglia.

That means that Mukuro was here, and probably Ken and Chikusa too. Any plans he had of escaping promptly fell out the window.

Mind made up, Tsuna silently apologised to his mother and brother and surrendered himself to the scientists surrounding him.

'I'm sorry Mama, Nari-nii. I can't go home yet. I can't leave my family behind.'

* * *

Author's note: I just wanted to say thank you 1827 for reviewing it means a lot to me ^-^


	5. Chapter 5

Tsuna stared sullenly at the roof of his cell. In the time he had been here, he had discovered several useful things.

Firstly, he learnt that he was probably in Italy. Except for the first Scientist he had met, he noticed that literally no one else spoke Japanese. All the conversations here were held in Italian.

Secondly, the scientists here were all idiots. None of them had paused to give a thought to the fact that Tsuna, someone they all knew was from Japan, clearly understood their speech as shown by the fact that he could obey all their commands.

Thirdly, the scientists were all paedophiles who clearly found pleasure in torturing children. Sure the scientists had nothing on a caffeine deprived Reborn but they still had one hell of a sadistic streak.

He _hated_ it here.

His whole body _hurt_. His muscles ached, he was covered in multiple busies and cuts, and he was exhausted from the never ending tests.

The whole place reeked of blood and every so often he would hear the tortured screams of children echo through the halls. Every time, his skin would itch with the urge to help them but he restrained himself.

'A few more months,' he would tell himself. 'just a few more months and I can reduce this place to ashes when Mukuro wakes up.'

He just prayed that the other children could hold on for that long.

Worst of all, he was lonely. So lonely. He missed his family. He missed Mama, Nari and his guardians. He even missed Reborn! He missed the days spent in the comfort of his large caring family. Of days playing in the snow and watching the fireworks together.

His only comfort was the bond he could feel between his brother and himself, formed in the brief moments their flames had brushed when they went active together. When things got too hard, he would close his eyes and reach out to his brother's flames. Basking in the familiar warmth. Sometimes he could even sense Mukuro's flames and the proof that he was alive and fighting gave him more strength than anything.

However, it didn't change the fact that there were scientists here that seemed to be going out of their way to make his procedures as painful as possible. He guessed it was probably due to the fact that he refused to let any signs of pain show on his face.

He had been through too much to even think of giving the scientists the satisfaction of hearing him scream. Reborn would never allow it. So every time he was hauled of to the lab, he would just detach himself from his body and let his mind wonder to happier times with his family. The only thing the scientists ever succeeded in doing was make his heart ache for his mist and his friends for having to go through all this as young, innocent children. (He was pretty sure even Mukuro could be considered innocent at some point. People couldn't be born as perverts...could they?)

Speaking of the Kokuyo gang, Tsuna had managed to spot Ken once. He had been coming back from the lab when he saw a scientist dragging a struggling young blonde pass him.

His eyes widened in recognition and he froze, startling the Man escorting him. Swerving around, he had just managed to catch a glimpse of the scientist raising his arm in preparation for a hit.

At this point, the man with Tsuna had turned around to grab him but something in Tsuna snapped when he saw little Ken flinch back, and he _moved_.

Flames bust to life on his body, burning the hand on him.

The man had recoiled immediately. Yelping in pain and surprised but Tsuna didn't notice.

He swayed almost lazily to his right, and he was gone. Only the briefest flash of sky flames could be seen.

He caught the scientist's arm before the blow could even come close.

Positioning himself between the scientist and the blonde, he snarled.

"What do you think you're doing?" he demanded.

The scientist had taken a step back, trembling in fear at the dark voice of the brunet before him.

Tsuna tightened his grip on the man's arm and Ken looked at Tsuna with something akin to awe.

"I asked, what do you think you're doing?"

The scientist was clearly one step away from wetting himself as he struggled in vain to dislodge himself from the bone crushing grip of a livid sky.

That was when Tsuna's watcher finally stepped in.

The man lunged at the brunet and Tsuna, startled, had barely managed to dodge.

He was forced to release his captive. The scientist, seeing his opportunity had tackled him. Pulling a syringe out of his pocket, he jammed it into the struggling boy.

The last thing Tsuna saw, was Ken yelling at him before being knocked out with a sharp blow to the neck.

After that incident, the scientists had tied a device resembling a choker around him that forcibly restricted his flames.

In conclusion, to say Tsuna was having the time of his life, was a complete and utter lie.

* * *

Tsuna jumped up from his position in the corner of his cell when he heard the tell tale creak.

Head snapping up to face the scientist, he stared at him in confusion.

Tsuna had only been there for a month but he had long learnt that everything here followed a gruelling schedule.

For him, every day he would be greeted by the scientist he had first met, to be dragged off to the lab for testing.

Said scientist clearly could hold a grudge and had taken to being as rough with him as possible after his first little escapade. So Tsuna had in turn, channelled his inner Gokudera and dubbed him the 'bastard'.

Anyways, every day without fail, Bastard would come at the same time, and bring him to the lab. In which he would spend at least a good hour sitting there and answering questions. They would usually tell him a mix of lies and facts and make him use his intuition to identify which was which. After that, he would under go a torturous regime where they tested the differences between a Vongola and an average human. They would force his 5-year-old body through military level obstacle courses to test his speed and agility. And pit him against various robots and sometimes even other kids to measure his combat abilities.

Sometimes they would come up with particularly sadistic tests like blindfolding him in a combat situation to see if his senses and intuition was strong enough to make up for vision. Or when they had shut him in a giant maze without food or water and told him to find his own way out. Even with his intuition guiding him, the maze was so large that it had taken him a whole day to get out. And by then he was already half dead from dehydration.

Finally, the day would generally end with the scientists cutting him open to see what made him tick or testing various drugs on him.

Though, thanks to the drugs, he had built up quite a good poison resistance. He would have to thank them for that. He'd take whatever the scientists could do over having to spend weeks choking down Bianchi's poison cooking while being held at gun point.

Moving on, his days here had all followed that set schedule so he was very surprised to see Bastard here when testing was already over for the day. He had already eaten the disgusting mush they called food so that eliminated the possibility of food delivery. That begged the question, what was he doing here?

Bastard sauntered towards him with his usual sadistic grin and Tsuna sighed in resignation.

"What do you want?" the Italian rolled of his tongue naturally.

Bastard cackled and Tsuna was disturbed by the pure menace dripping of his voice.

"Rejoice you little brat! You've been tested as compatible with the Angel project, testing starts immediately."

Bastard smirked as he grabbed Tsuna by the neck and dragged him out of the 'comfort' of his cell.

He was strapped onto a table and had a unknown clear serum injected into him.

His eyes widened as he felt it wrecked havoc in his system.

And for the first time since he got here, Tsuna opened his mouth and let out an ear piercing shriek.

Tsuna didn't need his intuition to know that his days here were about to get much, much worse.


	6. Chapter 6

Angels are the attendants of god. They are known as winged beings of the utmost purity.

As such, the angel project consisted of two goals. The first would be to attempt to put wings on a human, granting them the ability to fly.

The second, much more important objective would consist of trying to purify the subject's flames.

Now normally this would be completely unheard of. The idea had been briefly touched upon before. However, the plug was quickly pulled when nearly all the volunteers for the experiment had their flames overwhelm themselves and ended up burning to death.

Due to this, the experiment was pronounced as taboo and any who attempted it would soon find themselves on the run from the Vindice.

The Estraneo clearly didn't get the message.

Through extensive trail and error, they had theorised a working solution to the problem of flames overwhelming the user.

Firstly, they needed to introduce a special flame conductive material directly into the subject's body. As in, the material had to become part of their body.

A large amount of this material was required to make the experiment work. As such the scientists found themselves in a dilemma. They would either have to replace a large amount of the subject's body with the material, effectively turning then into a cyborg. Or they would have to find a way to attach it to the subject externally.

The first option was not really viable as the human body had too many intricacies for them to effectively replicate with the material so they had to go with the later.

Therefore, the dilemma lay in the fact that the scientists had been unsure of how to attach it. Some experiments in trying to have the material act as some sort of exoskeleton, have resulted in bulky armour that only slowed the user down due to the shear density of the material required to make the experiment even remotely possible.

Their breakthrough came when they were rooting through some old experiment files.

They came upon the Bird project which was their attempt to make bionic wings that would allow a person to fly.

They realised that they could use the material to construct extra functioning limbs, in this case wings, which would both solve their problem and at the same time increasing the subject's combat powers by granting them the ability to fly.

It was killing to birds with one stone.

The wings would be made with a combination of human and bird cells, together with their special material. Then introduced to the subject's body with a combination of sun and mist flames. This would allow the wings to become part of the subject, meaning the subject could control the wings like any of their other limbs and at the same time, ensure that they would grow with the subject.

Thus the Angel project was born.

Then the scientists found their second dilemma.

They needed a subject that was still young, with active and developing flames, which meant they needed to be younger than 13. Most importantly and troublingly, they needed to have extremely pure sky flames.

Now while rare, it wasn't unheard of to go flame active before your teenage years. However, the likelihood of you being a sky, was close to zero.

Sky flames were so rare and treasured that it was basically impossible for Estraneo to get their hands on one. Skies were protected and heavily guarded by everyone around them. The fact that they usually had guardians that would willingly give their lives to prevent their Sky from fallinh into the hands of others, really didn't help their chances.

So the question came, where could they find a young, bondless sky of high purity.

Sawada Tsunayoshi was a true godsend.

He was initially kidnapped to be used as research material for the Vongola bloodline. However in an incident where the subject had attempted to protect another, it was discovered that the child possessed, strong sky flames with an unparalleled purity.

They had quickly set worked to test its compatibility with the experiment. When it came back positive, they were practically jumping for joy.

They couldn't wait for the experiment to be a success.

* * *

Tsuna lay in a crumpled heap in the corner of his cell.

He rolled over to catch a glimpse of huge, white, feathery wings acting as his bed.

He curled into an even tighter ball, desperately trying not to think of how he had been unwillingly modified.

From what he's eavesdropped in the scientist's conversation, the Angel project he was being used for, had the main goal of purifying his flames.

The wings attached to him were made of a special material that was extremely flame conductive. They would serve as a catalyst to allow all the flames of the sky, except sky flames themselves, to pass through his body and forcibly try and purify his flames.

He honestly wondered why they didn't just stick a rod in him but he supposed maybe the scientists thought that was 'too lame'.

Cracking a weak smile at that thought, Tsuna continued to let his mind wonder.

He knew the wings would probably be useful for combat. It could significantly increase his flying abilities and make combat in air much easier for him. He knew that they gave him an advantage, and if there was one lesson Reborn had pounded into his head, it was to use anything to your advantage. Heck, he knew that Byakuran had a perchance to randomly sprouting wings and flying around.

He knew that, but it didn't change the fact that he hated it. He hated how they had messed with his body to their whims and expected him to be grateful for it. He hated how they were going around doing this to dozens of other children. Most of all, he hated how sometimes, just sometimes, he would stare at what had been done to him and wonder if he was really still human.

He grit his teeth and forced those thoughts out of his head. No. He couldn't waver. He would take whatever Estraneo could dish out and use it. He would grow stronger and protect his family properly this time. He had already failed once, nearly a second, he would never allow it to happen again. If it was to protect his family, he would even become a monster.

Shaking his head, he tried to move on to other things. He knew he was running out of time. From what he could gather, this experiment was doomed for failure for the simple fact that _he_ was their subject.

Their experiment required their subject to have pure sky flames. However, they hadn't given a thought to what would happen if their subject's flames were too pure.

The whole experiment was to progress in stages. In the first stage, they would inject a special serum that would attack the victim's flames. The serum would weaken his flames to a point where he would easily accept the flames they would pump into his body in the last stage, instead of actively fighting it. That was why the serum had hurt so much, enough so to overwhelm even him. It was attacking a person's very soul, their sense of self. Something had to be very wrong if they didn't feel any pain.

The second stage was when they would implant the wings. This took the most time. Tsuna spent the last 5 months training to actually use the wings. It mainly consisted of him being locked in a chamber spanning several levels, and getting pushed of a ledge. He was forced to use muscles that hadn't even existed to him till recently in an attempt to survive the fall.

He still remembered being confused when he found himself pushed through a door onto a high platform. At that point, he had spent the last 3 months or so learning to move the wings after recovering from the surgery. Progress had been slow as his brain had to adapt to the existence to whole new limbs in his body. He was pretty sure the only reason his body hadn't immediately rejected the wings was because he had been constantly regulating his harmony factor to accept the wings as a part of himself.

Anyway, he had found himself stuck on a platform 5 stories above the ground.

His confusion had faded quickly enough when he realised what they wanted him to do. The platform had began to retract and he found himself slipping into a panic.

' _Nononononono_! I don't have my flames! I can't fly!'

His 5-year-old body, despite undergoing Estraneo's special 'attention' could in no way survive a fall of that level without any flames to cushion him.

As the platform disappeared under his feet, he felt his mind draw a blank as he plummeted to his impending doom.

Just before he crashed headfirst into the ground, a thought flashed through his mind.

'I regret not at least trying to fly.'

He would later find himself lying on the ground in nothing but his underwear and found the chocker disintegrated at his feet.

After that, his chocker had been reinforced to the point where it wasn't just hard to manifest his flames but to circulate them too, and his days were spent falling off of platforms till he could consistently fly without a problem.

It had been almost as bad as Reborn's training, when he had made him climb the cliff to unlock Hyper Dying Will mode. And that was saying something.

The last stage was when they would pump flames into him and begin the purification process. This was the stage that he knew would inevitably fail.

For the last stage to succeed, the first had to too. And unfortunately for all of them, it didn't.

As narcissistic as it sounded, Tsuna knew that his flames were too pure and strong for the experiment to even come close to succeeding. Primo himself could testify.

A perk of being his true successor, Tsuna could meet Primo anytime he wanted. According to the founder himself, when Tsuna and his guardians created the Vongola X Gear, their flame purity had rivalled that of the first generation's. And when Tsuna had stood toe to toe with the Vindice, when his resolve had burnt so brightly that he entered the final stage of Dying Will, his flames had surpassed even that of Giotto's.

A flames' strength depends on the strength of their resolve but the purity of their flame was decided completely by one's personality. For a sky, it meant that the more open and accepting you were, the purer your flames. When Tsuna had accepted that Iemitsu was stronger than him, it had already paved the way to the next stage. Tsuna had shown acceptance to even Bermuda's desire to go through with a plan that would effectively kill his tutor, someone that had guided and believed in him, someone who was his second father. He had not approved of the plan but he had understood and accepted Bermuda's reason for wanting to go through with it. When he had managed to accepted even someone who wanted to kill the most important person in his life, his flame purity had surpassed any and all before him. Coupled with his resolve to do anything to free his tutor from his burden, Tsuna had entered Ultimate Dying Will mode.

And after that, his flames had only continued to grow in both strength and purity.

Even Kawahira had admitted that Tsuna was the very definition of a sky and the purest one in all of recorded history.

As such, Tsuna's flames, which had carried over from his past life, had been able to burn through the serum in minutes. Effectively ensuring the first stage would end in failure. As such, when the time came for the third stage rolled around, Tsuna's flames would be able to fight back and reject the foreign flames. There was just no way for the experiment to succeed, not in the face of Tsuna's overwhelming flame superiority.

Due to this, Tsuna knew he was running out of time. He had seen how Estraneo treated failed experiments. He was sure he would be 'disposed' of the second it was discovered that his experiment had failed.

He could only pray that Mukuro woke up before his third stage took place.

His amazing luck had made sure that he had only found out about all this after he had completed his second stage training so stalling was no longer an option.

He knew Mukuro was close, so close to awakening. He could feel his flames on the verge of bursting into existence.

But then, the sound of footsteps echoed through the hall.

They were headed right towards his cell.

When Bastard appeared grinning maniacally at his cell door, Tsuna realised, that Mukuro might not be close enough.

* * *

I hope that made sense...

I didn't study biology so there probably isn't any scientific backing to any of this.

Also thank you Guest, 1827 and angelaneahwalker for your reviews~ ^-^


	7. Chapter 7

Mukuro snapped awake.

Memories of another time, of another life, of happier days swirled around his mind.

Mukuro ached. He felt a gapping hole inside him. His Chrome, his bond with his soulmate was gone.

'No, not gone,' a traitorous part of him whispered. 'It was never there in the first place.'

He had yet to meet her in this time and he felt like a huge chunk of himself was missing without her. He wanted, no needed to see her. To make sure she was alive. To make sure that _this_ was real, that they really were given a second chance.

His flames were raging too. Reaching for a bond with a sky that wasn't there. They longed to find Harmony with someone he could not meet yet, at least not for years to come.

He grit his teeth and forced his flames back under control. Shacking of the clawing _emptiness_ inside him. He studied his situation behind a mask of serenity.

His arm unconsciously rose to rest on his right eye. He recognised this place. He was back at Estraneo, right after he had completed his 6 paths of reincarnation.

"Kufufu... looks like I've been given the brilliant opportunity to get my revenge" His smirk was downright nightmarish.

He leisurely disconnected himself form the countless machines, ripping out wires and disconnecting cords. He easily melted his restraints with some real illusions. All while plotting how he would express his 'gratitude' to his childhood captors.

When he felt it.

Strong, pure, _familiar_ sky flames curled around him, screaming in distress, begging for help.

He jerked up, before immediately collapsing to the ground, feeling the effects of a 6 month statist.

A scream ripped through the air.

Mukuro's flames roared. He reigned them in, casting an illusion on himself, he forced his body to move.

Before he knew it, he was crashing through the door.

Dashing down the hall, he let his flames guide him.

He pushed his body to the limit. Desperately searching for the source of the scream.

Coming to one of Estraneo's many testing sites, he came barreling into the room.

His flames burst out in outrage at the sight before him.

A familiar brunet was chained to the wall. He had giant wings sprouting out of his back which were connected to countless wires and machines. Each was pumping ridiculous amounts of flames into the writhing boy.

The Estraneo were experimenting on his sky, _his sky._

What. The. Hell.

Another scream erupted from his dear Tsunayoshi, and Mukuro snapped.

Mist flames swirled around the room as Mukuro glared at the scientists in the room.

They all simultaneously shuddered. Taking a step back from what could only be considered a devil from hell.

"N-Number 69. What are you doing here?" a braver (stupider) scientist who recognised him stuttered out.

The brunt of Mukuro's killing intent focused on the scientist and he immediately fell to his knees in fright, a mysterious stain appeared on his pants as an unpleasant odor filled the room.

"Oya Oya, I was just about to ask you the same thing," His bangs shadowed his eyes as an ominous red glint shone through his hair. "What the hell do you think you're doing to my sky?"

"Wha-?"

"Sk-sky?"

Dead meat A and Dead meat B yelped at the same time.

"Kufufu..." a trident materialised in his hand and he slammed it into the ground.

Mist flames surrounded the room. Instantly, all the scientists collapsed to the ground and started clawing at their head. A beautiful symphony of shrieks rang out.

"Suffer eternally in the deepest depths of hell for _daring_ to lay a hand on _my_ dear Tsunayoshi."

The trident disappeared from his hands and Mukuro's smile instantly disappeared.

He charged towards Tsuna disconnecting him from the machines and tearing of the chains at lightning speed.

He brought his little sky to his chest. Pulling him as close as possible to prove that _yes, this is real, he's here, he's_ _real_ _._

"Muku...ro?"

His eyes moistened (No, I was not crying!) and Mukuro tightened his hold on the smaller, too small, boy.

"Yes, dear Tsuna?" his flames reached out and circled the brunet, wrapping him in an illusionary blanket.

Sky flames reciprocated. And Mukuro nearly sighed in relief when he felt their bond click back in place.

"Missed yah." Tsuna muttered before he slipped into unconsciousness.

Mukuro took a moment to enjoy the feelings of acceptance and warmth, of belonging, of _home._

Before he jumped back and his flames recoiled when he finally felt the extent of flame damage his sky had suffered.

Metaphorical burns surrounded the brunet's soul. A result of having foreign flames pumped directly into him. They had tried to force his sky flames into submission.

Mukuro let out a low growl as he gently lifted his sky up, bridal style.

Oh, Estraneo was going to have hell to pay.

A quick pit stop to pick up his loyal minions later, Mukuro was seen laughing vindictively as he carved a bloody path through the Famiglia.

He did hold back to make sure he killed no one, couldn't have the Vindice coming after him now could he? Also, he knew killing would upset Tsuna and no one wanted an upset Tsuna.

That didn't mean he couldn't trap them in their worse nightmares and scar them for life.

As Mukuro reached out to free another child from the hell hole, he stopped a charging scientist dead in his tracks. Taking a moment to consider his options, Mukuro smirked when he finally decided on something. Waving his trident, the man was promptly dropped into a world of blood and gore.

Just as Mukuro was about to lead his followers out to freedom, he spotted a man running away while screaming expletives in Japanese. For some reason, something was nudging him to trap the man in the worst nightmare the deepest, darkest part of him could come up with. Never one to deny his instincts, Mukuro let his flames loose and paused to enjoy the show.

Yes, Mukuro was having the time of his life.

* * *

kudos to whoever figured out who the man at the end was!

Thank u TheAngelicPyro and VandQ for your reviews! ^-^


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